Even a good girl needs to let loose. Just ask Charlotte Casiraghi, striking daughter of Princess Caroline and one of the few members of Monaco’s scandal-prone Grimaldi clan to reach adulthood quietly.

As she turns 21 on Aug. 3, however, Charlotte is showing a rebellious streak that calls to mind some of her mom’s youthful headline-making behavior. In March she ended a three-year relationship with law student Félix Winckler and began dating London socialite Alex Dellal (ex-beau of Mick Jagger’s daughter Elizabeth). “It’s a mistake—he’s a modern-day Philippe Junot,” says a royal watcher, referring to Caroline’s disastrous first marriage to the French playboy. On the academic front, Charlotte, who lives in Paris and recently interned with a publishing house, is rethinking her plans to attend the Sorbonne this fall. Says a friend: “She’s fed up with her studies and doesn’t know what she wants to do with her life.”

For now she is having fun—hitting hot spots with glitzy pals such as Eugenie Niarchos (sister of Paris Hilton‘s ex Stavros), sunning herself on the family yacht and popping into boutiques like Dolce & Gabbana, Dior and, of course, her mom’s favorite, Chanel. But, says an acquaintance, underneath the glamour is a surprisingly unaffected person. “She’s very down-to-earth.”